<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="./lib//jquery.js"></script>
</head>
<body>
    <div class="app">
        你真是个天才!
    </div>
</body>
</html>
<script>
    var tools={/*你的代码*/}
   var obj={
    fn1:function ( ){
       $('.app').css('background','red')
       return obj   
    },
     fn2:function( ){
       $('.app').addClass('add')
       return obj
    },
    fn3:function( ){
       $('.app').click(function(){
        alert('总能整点东西')
       })
    }
   }
     obj.fn1().fn2().fn3()
// 执行触发，所有函数依

 
</script>
<style>

    .add{
        font-size: 30px;
    }
</style>